This invention relates to a solid-state imaging apparatus in which photo signals are read out through MOS type field effect transistors from a large number of photosensors arrayed in two dimensions.
A solid-state imaging apparatus wherein a plurality of photosensors such as photodiodes are arrayed in horizontal and vertical directions on a semiconductor substrate and wherein signal charges corresponding to the quantities of incident light as stored in the respective photosensors are sequentially read out through switches constructed of MOS type field effect transistors (hereinbelow, termed "MOS-FETs"), has the advantages that comparatively great charge signals can be handled and that the dark current is little.
The MOS type solid-state imaging apparatus, however, involves the problem that noise which develop from the switches for controlling the readout of the signals of the photosensors, especially the switches for the horizontal scanning are delivered in superposition on the photo signals from the photosensors.
The noise are classified into the so-called "fixed pattern noise" which appears as fixed vertical stripes on a reproduced picture, and the "random noise" which appears as irregular fluctuations. Although the cause of the former noise has been cleared up, any effective method of reducing the latter noise has not been found at present.